Such a heat exchanger comprises an inlet manifold and an outlet manifold interconnected by vertical U-shaped tubes.
The tubes are grouped together in heat-exchanger elements of a few tubes per element. The tubes in the same element are disposed in the same plane, and the various elements are aligned one behind the other with a certain spacing between them.
In known manner, such a hanging heat-exchanger having vertical tubes is suspended from the roof structure of the building by means of two suspension cradles: namely a cradle for supporting the heat-exchanger elements in the vicinity of the inlet manifold, and a cradle for supporting the heat-exchanger elements in the vicinity of the outlet manifold.
A known suspension cradle conventionally comprises two main beams situated on either side of the manifold, and suspended from the roof structure by rods, and a succession of transverse supports fastened transversely to the main beams.
The transverse supports are thus disposed one behind the other, and each support supports one heat-exchanger element. Each transverse support is a crosspiece made up of two channel-section members flanking the tubes of a heat-exchanger element. The two section members are interconnected at their ends by pieces that keep them spaced apart. The tubes of a heat-exchanger element thus rest on the crosspiece via a bush welded to one of the tubes of the heat-exchanger element, the tubes also being connected together.
Thus, the transverse supports constitute a succession of crosspieces fastened along main beams subjected to bending stress. The supports, whose rated temperature is high (550.degree. C. to 570.degree. C.), need to have considerable inertia and therefore need to be of considerable weight.